The grog is blue and the pirates do the limbo when you ship out with Pirate Adventures of the Chesapeake.

What is it about pirates that so entrances kids, anyway? Could it be the perpetual search for loot? The wearing of eye patches? The excitement of walking the plank? Or is it just that if you’re a kid on a trip with Pirate Adventures of the Chesapeake in Annapolis, you’re actually encouraged to yell “Arrgh, ya scurvy dogs!” as loud as you can, repeatedly, and your parents are required to more or less shut up. Yep, that’s probably it. From the moment Emily Tomasini (aka Captain Ruby) and her husband Mike (aka Captain Crabby) and their gang of buccaneers take hold of willing young imaginations, the streets of Eastport are full of skulking evildoers, the Severn River is the ocean wide, and the kids-pirates, that is-are front and center.

That’s how it was on a trip this spring when about two dozen three- and four-year-olds from Colonial Nursery School gathered at Annapolis City Marina to secure their eye patches, obtain tattoos, get decked out in pirate garb and be dubbed with their official pirate names, such as “Jellyfish Jake,” “Riptide Robbie,” “Seadog Sam” and “Keelhaulin’ Kailani.” From there, it was a two-block sneak-whispering, crouching, dashing and creeping all the way so no one would know where their pirate ship lay waiting-to the Sea Gypsy IV and an hour’s adventure on the Severn in search of treasure and the dastardly Pirate Pete (Captain Ruby’s worst enemy “because he stinks and he’s ugly!”).

The story (and the trip) began with a map that Captain Ruby said she found but then lost again. She needed the kids to help her find it, and before long they were crawling around the deck, searching, until someone came up with it-a stretch of canvas showing a painted map of Annapolis harbor, the Naval Academy and environs. From there, Captain Ruby encouraged the kids to pick out landmarks to help guide the ship toward the treasure, but not before encountering some excitement along the way. Certainly the high point was finding Pirate Pete aboard his ship (a little red runabout called Scallywag) anchored in the river and blasting him off the thing with broadsides from the Sea Gypsy’s water cannon. From there, it was a short run to the letter X on the map-and a corresponding X on a wooden float in the water near the Naval Academy bridge. After hooking the float, Captain Ruby had the kids help her heave a treasure chest up from the briny depths and lower it, still dripping, to the deck, where they opened it to find a trove of pieces of eight, little plastic sea creatures and plastic rubies and emeralds as big as the kids’ eyes. On the way home they found another sunken treasure, this a bottle of Pirate Pete’s grog (some sort of soda colored a blue that defied nature), and danced the limbo on deck while cruising Ego Alley.

It was all in a portion of a day’s work for Emily Tomasini of Severna Park, Md., who came up with the idea after seeing it being done in Cape Cod, Mass., where she was vacationing. She had been working on programs for middle school children in the Anne Arundel Department of Parks and Recreation (her background is in teaching), and she well knew there was nothing like this for kids in Annapolis. “She said, ‘I can do this,’ ‘‘ said her husband Mike (who, when he’s not Captain Crabby, sells surgical supplies). “So she started researching it and the boat and builder. It took her about five years start to finish.”

The boat is 38 feet long (with bowsprit), powered with two Suzuki 40-hp outboards. The fun end is the foredeck, a wide open area edged along the stout, high, fenced railings with small wooden pallets which serve as seats as well as step stools when it comes time to keep a lookout. (“All hands on deck!” is the cry from Captain Ruby that gets all the kids to kneel around her on the foredeck to study the map, plot strategy and-if need be-quiet things down a bit.) Parents sit aft on a series of benches where they can stay shaded under a wooden canopy and watch the antics up forward.

While developing her business plan and getting the boat built (by Than Drake of Cape Cod, who was operating the boat Tomasini had seen), Tomasini studied to get her Coast Guard captain’s license and worked on the schooner Imagine for two years. She finally launched the business in spring of 2003. “We did eighteen trips in May last year,” she said, and this year they did just under 100.

With up to six staff, the business is full-time from April through Labor Day, and weekends until Halloween, catering to kids three to eight years old. For information, call 443-398-6270 or go to www.chesapeakepirates.com.